The following description of the background of the invention is provided simply as an aid in understanding the invention and is not admitted to describe or constitute prior art to the invention.
Estrone [1,3,5(10)-estratrien-3-ol-17-one or 3-Hydroxy-1,3,5(10)-estratrien-17-one] or E1 is a C18 steroid hormone with a molecular weight of 270.37 daltons. Estrone is produced primarily from androstenedione originating from the gonads or the adrenal cortex. Estrone (or E1) is one of the three naturally occurring estrogens, the others being estradiol and estriol, that are natural to the human body. Its molecular formula is C18H22O2. Estrogens are primarily responsible for the growth of female characteristics in puberty and regulating the menstrual cycle. Estrone may be measured in women who have gone through menopause to determine their estrogen levels. It may also be measured in men or women who might have cancer of the ovaries, testicles, or adrenal glands. In premenopausal women estrone levels generally parallel those of estradiol. After menopause estrone levels increase, possibly due to increased conversion of androstenedione to estrone.
Methods for detecting specific estrone ions using mass spectrometry have been described. For example Nelson R, et al., Clinical Chem 2004, 50(2):373-84, and Xu X, et al., Nature Protocols 2007, 2(6):1350-1355 disclose methods for detecting various estrone ions using liquid chromatography and mass spectrometry. These methods derivatize estrone prior to detection by mass spectrometry. Methods to detect underivatized estrone by liquid chromatography/mass spectrometry are discussed in Diaz-Cruz S, et al., J Mass Spectrom 2003, 38:917-923, and Nelson R, et al., Clinical Chem 2004, 50(2):373-84. Methods to detect estrone by gas chromatography/mass spectrometry are disclosed in Nachtigall L, et al., Menopause: J of N. Amer. Menopause Society 2000, 7(4):243-250 and Dorgan J, et al., Steroids 2002, 67:151-158.